use nginx:alpine as base.

nginx/Dockerfile

@@ -1,15 +1,14 @@
-FROM nginx:latest
+FROM nginx:alpine
 
 MAINTAINER Mahmoud Zalt <mahmoud@zalt.me>
 
 ADD nginx.conf /etc/nginx/
-ADD laravel.conf /etc/nginx/sites-available/
+ADD laravel.conf /etc/nginx/conf.d/laravel.conf
 
 ARG PHP_UPSTREAM
 
-RUN echo "upstream php-upstream { server ${PHP_UPSTREAM}:9000; }" > /etc/nginx/conf.d/upstream.conf
-
-RUN usermod -u 1000 www-data
+RUN rm /etc/nginx/conf.d/default.conf \
+    && echo "upstream php-upstream { server ${PHP_UPSTREAM}:9000; }" > /etc/nginx/conf.d/upstream.conf
 
 CMD ["nginx"]
 

nginx/nginx.conf

@@ -1,6 +1,6 @@
-user www-data;
 worker_processes 4;
 pid /run/nginx.pid;
+daemon off;
 
 events {
   worker_connections  2048;
@@ -23,8 +23,5 @@ http {
   gzip on;
   gzip_disable "msie6";
   include /etc/nginx/conf.d/*.conf;
-  include /etc/nginx/sites-available/*;
   open_file_cache max=100;
 }
-
-daemon off;